As the shoutfest The Onion fittingly dubbed “The War for the White House” staggers towards its storm-soaked climax next Tuesday, there’s one fundamental question that I don’t think has really been answered yet:

Why are scientists such raving liberals?

Yes, science moves in that direction too.

We can’t deny that we look that way to the general public. Nature, which is to science what the Wall Street Journal is to investment banking, unabashedly endorsed President Obama for re-election. Sixty-eight Nobel laureates signed an open letter making the same endorsement. If you follow scientists or science journalists on Twitter, your feed will seldom go an hour without someone advocating Democratic policies or candidates. And by the highly polarized standards of our time, voting for Democrats automatically constitutes raving liberalism, as surely as voting for a Republican is diagnostic of reactionary wingnuttery.

Never mind that “scientists” are far from homogeneous. We’re a group whose principal unifying traits are independent thought, distrust of authority, and a love of intense, arcane arguments. We will agree – slowly, grudgingly – to certain broad, general principles, but only in the face of overwhelming evidence. Even then, the “scientific consensus” inevitably contains thousands of small but intense disagreements about the details. Virtually every biologist worthy of the title will concur that complex life evolved from simpler life, and continues to do so, but if you ask whether this particular species diverged sooner or later than that one, or even what the word “species” means, you’ll immediately see taxonomists disemboweling each other. So how can we possibly have a unified political agenda?

We don’t, of course. Talking to scientists is a big part of my job, and when specific policies come up, the conversation inevitably reveals diverse and unpredictable opinions. Scientists in industry sometimes sound like good Republicans, advocating smaller government, less regulation, and unrestrained markets, while academic researchers sometimes favor more government funding, stronger regulations, and less industry involvement, like stereotypical Democrats. Other times it’s the reverse, and the same scientist commonly appears on different sides of the aisle on different issues. Like taxonomists debating the proper classification of a grasshopper, we’re all over the map.

There’s also some diversity in scientists’ assessments of the two major political parties, but in broad, general terms the group leans toward the Democrats. Some have theorized that this is because Democratic candidates are more likely to understand (or at least purport to understand) the complexity and nuances of major policy questions, whereas Republicans prefer pat slogans that oversimplify the issues, and scientists understand that oversimplification is dangerous. I think that’s bullshit. Bumper stickers that proclaim “Healthcare is a human right” are no less jingoistic than “Abortion stops a beating heart.” Both are willfully deceptive oversimplifications.

Nor does either side’s constituency have a monopoly on the rational treatment of data. If you like to ignore the overwhelming evidence that humans are changing the global climate, odds are you vote with the red states. But if you irrationally oppose genetically modified crops, then I’ll bet the donkey is your mascot. Anti-vaccine advocates, animal rights groups, and the anti-psychiatry movement also draw mostly from the left side of the aisle. Indeed, I suspect that if we held a big conference for everyone who advocates profoundly irrational policies, we’d draw a solid Democratic majority.

Given the blatant stupidity on both sides, you might expect scientists to just throw up their hands, pick randomly, and say “don’t blame me, I voted for Kodos.” I know some who do. There is, however, one crucial difference between the two parties, at least in their current incarnations. Considering what I said a few paragraphs ago, I certainly wouldn’t presume to speak for all scientists, but this difference is the main reason my own voting record has favored Democrats, and I suspect others may have reached similar conclusions.

Political parties are like dysfunctional families. Everyone has a few crazy cousins somewhere, so the question is how to deal with them. The Democratic party tolerates but marginalizes its anti-science crusaders. The Republican party hands them the keys. That’s why the Bush administration and Republicans in Congress neutered the EPA, obstructed any meaningful environmental legislation that came up, and hamstrung public health agencies and some branches of research. Their crazy cousins didn’t like what the science was saying, so they banned it. When Obama was elected, he came into office with a commanding majority in Congress. If the two parties were truly equivalent in their stupidity, we would have seen vaccination, genetically modified crops, and animal research in the crosshairs. Instead, the Democrats nodded and smiled at their crazy cousins, then went about enacting (mostly) rational and moderate policies in all of those areas.

I don’t think this comparative Democratic rationality is deliberate. Instead, it stems from the way the two parties operate. The GOP is a carefully engineered political machine, which is why it’s so frighteningly efficient when its candidates gain power. By grabbing a few critical levers, a small, unhinged minority can take control of the whole juggernaut, and that’s exactly what we’ve seen in recent years. The Democratic party is more of an amoeboid organism, sending out pseudopodia in all directions, averaging the inputs from innumerable signals, and finally crawling in a specific direction for a short distance before repeating the whole cycle. It’s slow, inefficient and cumbersome, but very unlikely to run off the rails.

If that sounds like faint praise, it’s because it is. Should the Republicans ever hand the controls over to scientists, do a teardown on their platform, and adopt consistent, evidence-based policymaking as their primary ideology, I’d be thrilled to join them. Until then, I’ll be voting for these folks.